<head>
    <script src = "Sci_Cal.js"></script>
    <link rel="stylesheet" href="Sci_Cal.css">
  </head>
  <form name="sci-calc">
   <table class="calculator" cellspacing="0" cellpadding="1">
     <tr>
       <td colspan="5"><input id="display" name="display" value="0" size="28" maxlength="25"></td>
     </tr>
     <tr>
       <td><input type="button" class="btnTop" name="btnTop" value="C" onclick="this.form.display.value=  0 "></td>
       <td><input type="button" class="btnTop" name="btnTop" value="<--" onclick="deleteChar(this.form.display)"></td>
       <td><input type="button" class="btnTop" name="btnTop" value="=" onclick="if(checkNum(this.form.display.value)) { compute(this.form) }"></td>
       <td><input type="button" class="btnOpps" name="btnOpps" value="&#960;" onclick="addChar(this.form.display,'3.14159265359')"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="%" onclick=" percent(this.form.display)"></td>
     </tr>
     <tr>
       <td><input type="button" class="btnNum" name="btnNum" value="7" onclick="addChar(this.form.display, '7')"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="8" onclick="addChar(this.form.display, '8')"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="9" onclick="addChar(this.form.display, '9')"></td>
       <td><input type="button" class="btnOpps" name="btnOpps" value="x&#94;" onclick="if(checkNum(this.form.display.value)) { exp(this.form) }"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="/" onclick="addChar(this.form.display, '/')"></td>
     <tr>
       <td><input type="button" class="btnNum" name="btnNum" value="4" onclick="addChar(this.form.display, '4')"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="5" onclick="addChar(this.form.display, '5')"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="6" onclick="addChar(this.form.display, '6')"></td>
       <td><input type="button" class="btnOpps" name="btnOpps" value="ln" onclick="if(checkNum(this.form.display.value)) { ln(this.form) }"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="*" onclick="addChar(this.form.display, '*')"></td>
     </tr>
     <tr>
       <td><input type="button" class="btnNum" name="btnNum" value="1" onclick="addChar(this.form.display, '1')"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="2" onclick="addChar(this.form.display, '2')"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="3" onclick="addChar(this.form.display, '3')"></td>
       <td><input type="button" class="btnOpps" name="btnOpps" value="&radic;" onclick="if(checkNum(this.form.display.value)) { sqrt(this.form) }"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="-" onclick="addChar(this.form.display, '-')"></td>
     </tr>
     <tr>
       <td><input type="button" class="btnMath" name="btnMath" value="&#177" onclick="changeSign(this.form.display)"></td>
       <td><input type="button" class="btnNum" name="btnNum" value="0" onclick="addChar(this.form.display, '0')"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="&#46;" onclick="addChar(this.form.display, '&#46;')"></td>
       <td><input type="button" class="btnOpps" name="btnOpps" value="x&#50;" onclick="if(checkNum(this.form.display.value)) { square(this.form) }"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="+" onclick="addChar(this.form.display, '+')"></td>
     </tr>
     <tr>
       <td><input type="button" class="btnMath" name="btnMath" value="(" onclick="addChar(this.form.display, '(')"></td>
       <td><input type="button" class="btnMath" name="btnMath" value=")" onclick="addChar(this.form.display,')')"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="cos" onclick="if(checkNum(this.form.display.value)) { cos(this.form) }"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="sin" onclick="if(checkNum(this.form.display.value)) { sin(this.form) }"></td>
       <td><input type="button" class="btnMath" name="btnMath" value="tan" onclick="if(checkNum(this.form.display.value)) { tan(this.form) }"></td>
    </tr>
   </tabel>
  </form>
       
       